Thousands of citizens of Pakistan's Lahore, one the world's most polluted cities, complained Thursday of breathing difficulties and irritable eyes as a blanket of thick smog was forecast to persist for several days.

The world's nations must urgently ramp up commitments to cut planet-warming carbon emissions to avoid "human tragedy," the United Nations warned on Thursday.

As they stand, the measures -- which do not kick in until 2020 -- would still allow average global temperatures to climb as high as 3.4 degrees Celsius (6.1 degrees Fahrenheit) by century's end, a recipe for massive climate damage, the UN Environment Programme said in its annual "Emissions Gap" report.

Diplomats from 196 nations gather from Monday for 12-day UN climate talks tasked with charting a path for capping global warming at "well below" two degree Celsius (3.6 Fahrenheit) above pre-industrial era levels. 

Environmental campaigners in Britain won a High Court legal battle on Wednesday over the government's failure to tackle air pollution to meet European standards.

Some 300 million children live with outdoor air so polluted it can cause serious physical damage, including harming their developing brains, the United Nations said in a study released Monday.

Nepal has successfully drained part of a giant glacial lake near Mount Everest, averting risk of a disastrous flood that could have threatened thousands of lives, officials said Monday.

Scientists say climate change is causing Himalayan glaciers to melt at an alarming rate, creating huge glacial lakes which could burst their banks and devastate mountain communities.

Iran's vice president and environment chief, Massoumeh Ebtekar, has told AFP that the West's failure to fully implement the nuclear deal and lift sanctions are endangering her country's efforts to meet climate targets.

Agreement was reached Friday to create a vast US and New Zealand-backed Antarctic marine sanctuary in the Ross Sea -- the world's largest -- at a meeting of the Conservation of Antarctic Marine Living Resources (CCAMLR) in Hobart.

In the crosshairs of anti-whaling nations, Japan defended its annual Southern Ocean whale hunt, insisting it was gathering scientific data even as detractors accused it Thursday of harvesting meat under false pretenses.

Australia is set to experience more heatwaves, with record-breaking hot weather becoming "normal" across the continent as climate change pushes up land and sea temperatures, a government report warned Thursday.

The biannual State of the Climate report from the Bureau of Meteorology (BOM) and national science body CSIRO said Australia was already experiencing more extremely hot days and severe fire seasons, and projections showed temperatures would likely keep rising.